Robot arm

Abstract

A robot arm with high productivity capable of preventing a decelerator from being damaged is provided. A robot arm according to an embodiment of the present disclosure is a robot arm in which a second member is rotationally coupled to a first member via a decelerator that accommodates lubricant therein, the robot arm including: a circulation path in which the lubricant is circulated via the decelerator; a storage part that is arranged in the circulation path and stores the lubricant; and an actuator configured to circulate the lubricant, in which the storage part is provided with a filter for capturing impurities in the lubricant in such a way that the filter covers an outlet of the lubricant in the storage part.

What is claimed is: 
     
       1. A robot arm, comprising:
 a second member rotationally coupled to a first member via a decelerator that accommodates lubricant therein; 
 a circulation path in which the lubricant is circulated via the decelerator; 
 a storage part that is arranged externally from the decelerator in the circulation path and stores the lubricant; and 
 an actuator configured to circulate the lubricant in the circulation path, 
 wherein the storage part includes an inlet and an outlet for the lubricant, and a filter covers the outlet so as to capture impurities in the lubricant as the lubricant flows through the filter and the outlet, 
 the actuator comprises a piston pump that pushes out the lubricant, a piston included in the piston pump moving using the rotation of the second member with respect to the first member as a drive source, 
 the piston pump comprises a cylinder that accommodates the piston in such a way the piston can be moved and is arranged in the circulation path, and a rod having one end part fixed to the piston and having an other end part protruded from the cylinder, the cylinder being fixed to the first member, 
 the actuator comprises:
 a rotation transmission part that is rotated about a rotation axis of the second member when the second member is rotated with respect to the first member and includes one of a convex part and a concave part; and 
 a rotated transmission part that is fixed to the other end part of the rod and includes the other one of the convex part and the concave part with which the rotation transmission part is engaged, and 
 
 the convex part falls out of the concave part when the rotation of the second member with respect to the first member falls outside a predetermined rotation range. 
 
     
     
       2. The robot arm according to  claim 1 , wherein
 the outlet of the lubricant in the storage part is formed in an end part on a side opposite to a gravity direction in the storage part, and 
 the filter is fixed to the end part on the side opposite to the gravity direction in the storage part in such a way that the filter covers the outlet from an inside direction of the storage part. 
 
     
     
       3. The robot arm according to  claim 1 , wherein the actuator pushes out the lubricant using the rotation of the second member with respect to the first member as a drive source. 
     
     
       4. A robot arm in which a second member is rotationally coupled to a first member via a decelerator that accommodates lubricant therein, the robot arm comprising:
 a circulation path in which the lubricant is circulated via the decelerator; 
 a storage part that is arranged in the circulation path and stores the lubricant; and 
 an actuator configured to circulate the lubricant, 
 wherein the storage part is provided with a filter for capturing impurities in the lubricant in such a way that the filter covers an outlet of the lubricant in the storage part, 
 wherein the actuator comprises a screw pump that pushes out the lubricant, a screw included in the screw pump being rotated using the rotation of the second member with respect to the first member as a drive source. 
 
     
     
       5. The robot arm according to  claim 4 , wherein the actuator comprises a ratchet mechanism that transmits one rotation of the second member with respect to the first member to the screw and interrupts transmission of another rotation of the second member with respect to the first member to the screw. 
     
     
       6. The robot arm according to  claim 1 , wherein the actuator comprises:
 a through-hole that penetrates through the piston; and 
 a valve mechanism configured to open the through-hole when the second member is rotated in one direction with respect to the first member and the piston is moved and to block the through-hole when the second member is rotated in another direction with respect to the first member and the piston is moved. 
 
     
     
       7. A robot arm in which a second member is rotationally coupled to a first member via a decelerator that accommodates lubricant therein, the robot arm comprising:
 a circulation path in which the lubricant is circulated via the decelerator; 
 a storage part that is arranged in the circulation path and stores the lubricant; and 
 an actuator configured to circulate the lubricant; 
 wherein the storage part is provided with a filter for capturing impurities in the lubricant in such a way that the filter covers an outlet of the lubricant in the storage part, 
 a first base having a peripheral surface in which an arc surface is provided, the first base being the first member; 
 a second base that is rotationally connected to the first base about a first axis that passes the center of the arc surface of the first base, the second base being the second member; 
 an arm part connected to the second base in such a way that it can be rotated about a second axis perpendicular to the first axis; 
 wherein the actuator comprises a first actuator and a second actuator; 
 the first actuator comprises a screw pump fixed to the second base and a roller that is connected to the screw pump and contacts an arc surface of the first base, the first actuator being capable of transmitting the rotation of the second base with respect to the first base to the screw pump via the roller; 
 the second actuator comprises a piston pump fixed to the second base, a rotation transmission part that is fixed to the arm part and includes one of a convex part and a concave part, and a rotated transmission part that is fixed to a tip end part of a rod of the piston pump and includes the other one of the convex part and the concave part that can be engaged with the rotation transmission part, the second actuator being capable of transmitting the rotation of the arm part with respect to the second base to the piston pump via the rotation transmission part and the rotated transmission part, and 
 wherein the second base is provided with a first motor and a first decelerator for rotating the second base with respect to the first base and a second motor and a second decelerator for rotating the arm part with respect to the second base. 
 
     
     
       8. The robot arm according to  claim 1 , wherein the storage part has a hollow-box shape including a lid, and the storage part is fixed to an outer surface of the second member in such a way that it can be attached and detached from the second member.